11 About the Authors

Dr. Kamini Singha is a Professor in the Department of Geology and Geological Engineering and Associate Dean of Earth and Society Programs at Colorado School of Mines in Golden, Colorado, USA. She has a Ph.D. in Hydrogeology from the Department of Geological and Environmental Sciences at Stanford University in 2005 and a Bachelor of Science degree with Honors in Geophysics from the Department of Geology and Geophysics at the University of Connecticut in 1999.

Her research interests rely on fluid flow and solute transport in porous media and fractured rock as well as groundwater-surface-water interactions; integration of hydrologic and geophysical techniques; quantification of the “geophysical footprint” to constrain the operation of parameters controlling fluid flow and solute. She has worked a wide variety of multidisciplinary problems including imaging tree water use with electrical geophysics; mapping water quality degradation and its connections to human behavior; imaging moisture dynamics in desert ecosystems; exploring changes in infiltration after fire; and quantifying kinetics of iron reduction given electrical measurements.

Dr. Singha is an award-winning teacher, a recipient of a U.S. National Science Foundation CAREER award and the Early Career Award from the Society of Environmental and Engineering Geophysics, a Geological Society of America Fellow, and a former Fulbright Scholar. She served as the U.S. National Groundwater Association’s Darcy Lecturer in 2017, and is a current Editor at Water Resources Research.

She currently teaches Groundwater Engineering, Geological Data Analysis, and Field Methods in Hydrology at the Colorado School of Mines. For a full, up-to-date list of her publications, please click here.

Dr. Timothy C. Johnson is a computational scientist in subsurface geophysical imaging and interpretation related to complex environmental challenges and energy applications. He is nationally and internationally recognized for his work in electrical resistivity tomography (ERT) as a characterization and monitoring technology. He pioneered the development of E4D-RT, a real-time, four-dimensional subsurface imaging software that allows scientists to “see” subsurface processes and solutions in real-time. He and his team received a prestigious R&D 100 Award in 2016 for this tool. He joined Pacific Northwest National Laboratory in 2010 as a senior research scientist. He worked at Idaho National Laboratory from 2007-2010 and, before that, was a staff engineer at American Geotechnics. He is focused on joint inversion of multiple geophysical techniques using parallel computing to improve time-lapse imaging.

Dr. Johnson has a Doctorate degree in Geophysics in 2006, a Bachelor’s degree in Civil Engineering in 2001, and a Bachelor’s degree in Geophysics in 1999, all from Boise State University. He has received awards and recognitions, including: Laboratory Director’s Award for Exceptional Engineering Achievement in geophysical imaging, 2017; R&D 100 Award for Real-Time Four-Dimensional Subsurface Imaging Software (E4D-RT – (https://e4d.pnnl.gov) in 2016; and R&D Magazine honor for inventors of 100 most technologically significant products each year. He has the U.S. Patent No. 9,772,423, September 26, 2017, “Method Of Imaging The Electrical Conductivity Distribution Of A Subsurface”. The full list of his publications can be found here.

The bulk of Dr. Johnson’s research has been commissioned by the U.S. Department of Energy and Department of Defense, focusing on developing joint geophysical methods for investigating shallow subsurface contamination issues, for understanding stress and fluid flow in deep crystalline rock systems, and for understanding the effects of underground explosions.

Dr. Frederick D. DayLewis a Chief Geophysicist and Laboratory Fellow with the Pacific Northwest National Laboratory’s Earth Systems Science Division. He received a Ph.D. in Hydrogeology from Stanford University (2001) and a Bachelor of Science and Bachelor of Arts in Hydrology and English from the University of New Hampshire (1994). Prior to starting at Pacific Northwest National Laboratory, he was a Research Hydrologist at the U.S. Geological Survey, where he developed and applied hydrogeophysical methods in groundwater studies across the U.S. Dr. Day-Lewis conducts applied research on characterization, monitoring, and understanding of hydrologic processes, with current emphases on groundwater/surface-water interactions and fractured rock. Recent activities include studies to improve the understanding of hyporheic zone processes and measurements of properties controlling contaminant storage in geologic materials. He has experience using electrical, radar, and electromagnetic geophysical methods as well as distributed temperature sensing. In this work, he also develops software for improved analysis and visualization of related data (1DTempPro, DTSGUI, FLASH-R). As part of his technology transfer efforts, Dr. Day-Lewis collaborates with state and federal partners including SERDP, ESTCP, DOE, EPA, and others to support informed decision-making on the selection and application of hydrogeophysical tools and methods. He also develops decision support tools (SEER, FRGT-MST) to help practitioners and environmental site managers identify near-surface geophysical methods appropriate for a given project’s goals and site conditions.

Dr. Day-Lewis co-edited the American Geophysical Union monograph “Subsurface Hydrology: Data Integration for Properties and Processes” (2007). He is a Fellow of the Geological Society of America, past President of the American Geophysical Union’s Near Surface Geophysics Section, and past Vice President of the Environmental and Engineering Geophysical Society. He has served as an Associate Editor for Water Resources Research, Groundwater, Hydrogeology Journal, and Geosphere.

Dr. Lee D. Slater, after study in the United Kingdom, a postdoctoral appointment, and initial tenure-track faculty position in the U.S., joined Rutgers University in 2002 to continue performing research in hydrogeophysics. He is currently a Henry Rutgers Professor in Geophysics at Rutgers University Newark and an internationally recognized expert in near-surface geophysics and hydrogeophysics. His research is primarily focused on the use of electrical geophysical technologies for subsurface characterization and monitoring. He has published extensively, including 150 papers in peer-reviewed international journals of hydrogeology and geophysics, as well as being a co-author of the recent book “Resistivity and Induced Polarization: Theory and Applications to the Near Surface Earth”.

Dr. Slater has served as principal investigator on multiple research and technology demonstration projects funded by the U.S. Department of Defense, U.S. Department of Energy, U.S. Department of Agriculture, U.S. National Parks Service, and National Science Foundation. He has also served in prominent leadership roles in the academic geophysical community, including Chair of the Near Surface Geophysics Focus Group of the American Geophysical Union (AGU), Chair of the AGU Hydrogeophysics Technical Committee, and President of the Environmental and Engineering Geophysical Society (EEGS).

Dr. Slater currently serves as Associate Editor of Water Resources Research (WRR) and he recently edited a new volume on Near Surface Geophysics published in the 2nd Edition of the Treatise on Geophysics, part of the Elsevier Major International Reference series. He has served on multiple advisory boards for large interdisciplinary hydrogeological research projects in Europe.

He was the recipient of the 2013 Harold B. Mooney award of the Society of Exploration Geophysicists (SEG). His numerous Ph.D. graduates have mostly gone onto academic positions and are now making their own contributions to advancing research in hydrogeophysics. In 2018 Dr. Slater was elected Fellow of the American Geophysical Union (AGU), with the citation: “for visionary experimentation in near-surface geophysics that has advanced understanding of subsurface hydrogeological and biogeochemical processes”.


Electrical Imaging for Hydrogeology Copyright © 2022 by Kamini Singha, Timothy C. Johnson, Frederick D. Day Lewis and Lee D. Slater. All Rights Reserved.